Appliance for bending tubes, rods, and the like



1944- F. c. DRAPER ET AL 2,366,012

APPLIANCE FOR BENDING TUBES, RODS, AND THE LIKE Filed Aug. 25, 1945 5 Sheets-Sheet 1 FIG].

Attorney Dec. 26, 1944. c, W F ET AL 2,366,012

APPLIANCE FOR BENDING TUBES, RODS, AND THE LIKE Filed Aug. 25, 1943 5 Sheets-Sheet 2 at, 6 nventorS v 4 Misha A itorney Dec. 26, 1944. F. c. DRAF'ER ET AL 2,356,012

APPLIANCE FOR BENDING TUBES, RODS, AND THE LIKE Filed Aug. 25, 1945 5 Sheets-Sheet 5 I venlors Attorney Dec. 26, 1944. I I F. c. DRAPER ET AL 2,366,012

APPLIANCE FOR BENDING TUBES, RODS, AND THE LIKE Filed Aug. 25, 1943 5 Sheets-Sheet 4 I nvenlo 8 7 M W.

A tlorney Dec. 26, 1944. F. c. DRAPER' ET'AL 2,366,012

APPLIANCE FOR B-ENDING TUBES, RODS, AND THE LIKE Filed Aug. 25, 1943 5 Sheets-Sheet s FIG/l. FIG /2 I]: I0: ,I F c: i 5 i:

I l4- 5.- i F;

l l a FIGS. 46 5 :w I: i

Attorney j Patented Dec. 26, 1944 APPLIANCE roe BENDING TUBES, RODS,

AND THE LIKE Frederick Cecil Draper, Chipping Sodbury, and John Shaw, Wotton-under-Edge, England, assignors toParnall Aircraft Limited, Yate, near Bristol, England, aBritish company APDlicationAugust 25, 1943, Serial No. 499,990 In Great Britain October 20, 1942 8 Claims.

This invention relates to appliances for bending tubes, rods and the like. Theinvention is. particularly concerned with apparatus for form ing a number of bends in a length of metal tube which can bebentin the cold, such as tubes of annealed copper,.mild steel, or aluminum alloys which have been normalised.

It is often necessary to provide a length of metal tubing with a comparatively complicated, set of bends which may be irregularly spaced along the length oi the tube and not only may have to be made about axes at right-angles, but also on occasion about oblique axes, and indeed bends of different radii may have to be made in the same length ortubing. An example of such bends is set out in the specification of patent application Serial No. 473;,737, filed 27th January 1943; an example of the application of such tubes occurs in hydraulic systems, such as, for example, tubes supplying hydraulic pressure to the'turrets of aircraft. It. is evident from the said prior patent specification that when a complicated set of bends has to be made by bending the tube around a series of forming dies, the dies have to be set up with Various spacings between neighbouring dies and the dies'have to be set up in various angular positions, and that if separate supporting brackets and jigs are. employed" for each. bend, thesefixings involve a veryconsiderable number ofparts for a singl Job and in addition. the same parts are not. easily adaptable for different jobs.

The object. Qrthe, presentinvention i to provide a set of fixings for such bending dies which can deal with bends of the d f e en n s e countered in practice and for which a minimum number of standardised parts only is necessary.

According. to the present invention, a jig or ing bracket for supporti g the dies or formers enables thelatter to befixed in position for carrying out all the varieties of bending operation which are needed with the use of relatively few parts; the bracket is ofright-angled section with two flat plates at right-angles, one utilised for securing the bracket in position and the other drilled with a number of holes consisting of a line of holes lying along a circular arc struck about another hole as centre. An arm which carries the forming die directly or indirectly is fixed to the drilled bracket plate in one of anumber of one. of the plates of the bracket, each lying at the corner of an equilateral triangle with its apex near the edge of the drilled plate and with two series of further holes lying on circular arcs which extend from the apex of the triangle to the other =two corners, each being struck about one of the other corners as centre. If two of the corner holes lie on a line parallel to the plate used for fixing, if those two holes are used for securing the former arm, then the latter lies with its cen tre lineparallel to the plate used for fixing. That plate can besecured to a horizontal support or to a Vertical support. In the former case, the centre line of th former arm is horizontal, but

to the support and then" the drilled plate of the other one can be used for securing the former arm in various angularpositions parallel to the supporting-surface.

It has been indicated that the forming die need not be secured directly to the former arm. A right-angle piece maybe secured to the former arm and the forming die secured to that angle piece in various oblique positions.

The former armmay be a steel bar of rectangular cross-section drilled near one end with possible angular positions merely by the use of a pair of securing bolts which engage one of the holes in the line andthe hole at the centre of the are on which the line of holes lies. In a convenient-arrangement, three holes are drilled in a hole to receive one of the securing bolts which can be fixed by anordinary nut. Further along the former arm, another bolt passing. through another hole in th fixing bracket may be provided witha finger nut. 'In the former arm it may pass through a slot opening to one side of the arm, in which case by loosening the finger nut, the former' armmaybe swung out of the way, which is convenient ins'olne cases since otherwise it might interfere with the formation of a previous bend in the pipe.

Other positions for the forming die may be obtained by employing former arms which are not straight bars but are cranked either to the left or to. the right, and the forming die maybe offset. by using aformer arm which is cranked twice, that is to say; which has an inclined portion proceeding from the part secured to the fixingbracket, and a further end portion turned parallel again to the part; secured to the fixing bracket.

pipe, the latter is cut ofi to a predetermined length and the bending is started after the end of the pipe has been registered against an adjustable stop. This may consist of a vertical bar standing up from the base of the jig to which the brackets are fixed and having projecting from it a horizontal screw which is adjustable and locked in the adjusted position by nuts. If the pipe is to be bent in both directions from an intermediate point, it needs to be supported near that point in clamps, each of which consists of a vertical bar upstanding from the base of the jig with horizontal holes at different heights to receive a bolt provided with a finger nut for holding a clamping jaw against the pipe at any desired height.

In order to illustrate how a few standardised parts can be used in carrying out a relatively complicated series of bends in a length of metal pipe, an example of a set-up in accordance with the invention, together with the necessary parts for use in it, will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a general plan view of the complete jig employed; 7

Figure 2 is a plan to an enlarged scale and showing more detail of the parts of the jig to the left of the line X-Y in Figure 1; and

Figure 3 is a similar plan of the parts of the jig to the right of the line X--Y in Figure 1;

Figure 4 is an elevation of the fixing bracket employed showing a simple rectangular former arm secured in position;

Figure 5 is a section on the line V-V in Figure 4 showing the method of securing the forming die to the former arm;

Figure 6 is a section on the line VI-VI, in Figure 5;

Figure '7 is an end elevation showing a cranked former arm secured to a fixing bracket;

.. Figure 8 is a plan view showing a cranked former arm fixed to the fixing bracket with an angle member for holding the forming die;

Figure 9 is a plan View of an arrangement in which a double cranked former arm and angle member are employed;

Figure 10 is an elevation of the setting stop employed;

Figures 11 and 12 are two elevations at rightangles of a suitable form of clamp for the pipe in the neighbourhood of the first bend;

Figure 13 is a front elevation, and

Figure 14 a side elevation of a simple form of bending tool shown in position at the commencement of a counter-clockwise bend.

The example taken for the purpose of illustration involves eight bends in a length of pipe shown at I in Figures 1 to 3. The shape of the bent pipe is shown at IA in those figures, and it will be noted that it is to have a straight length IB near its middle portion. It is convenient in such a case to start bending from a point near the middle towards one end, which is towardsthe left in the drawings, and then to complete the bends by proceeding in the other direction towards the right in the drawings. The pipe I is cut to the predetermined length and has its lefthand end, or in the case in which hydraulic pressure is maintained within the pipe during the bending, a plug closingthe end of the pipe, brought against a setting stop 2. This setting stop is shown in detail in Figure 10 and like the other parts of the jig, it is fixed to a bed or base consisting for simplicity of a straight section 3 of reinforced moulded synthetic resin to which are fixed a number 'of branching portions 4 of the same material.

The setting stop, as seen particularly in Figure 10, consists of a vertical bar 5 which extends up from between two angle brackets 6 fixed by bolts to the bed 3. A bolt 6a is tightened up to hold the bar 5 in the desired position from which it may easily be swung by hand when it is necessary to move the setting stop out of the way. The stop member proper consists of a stud 1 projecting from the vertical bar 5 and capable of precise adjustment by means of nuts 8 which also serve to fix it in the adjusted position. The pipe I is supported in a pair of clamps 9 which engage the straight middle part IB. The construction of clamp employed is shown in detail in Figures 11 and 12. Each consists of a pair of angle brackets I0 fixed by bolts to the base 3 and a vertical bar II standing up from the brackets I 0. The bar- II is drilled with holes spaced a short distance apart along the length of the bar, as shown at I2. This enables the pipe I to be supported at any desired height from the bed 3. The pipe I is held against the bar I I by a clamping jaw I3 of rectangular shape and held by a bolt I4 placed through an appropriate hole I2 to hold the pipe I at the desired height. The jaw I3 is held in position by a finger nut I5, and in order to maintain it parallel to the bar I I, it also engages the rounded head I6 of a short bolt passed through the hole I2 lower down as seen in Figure 12. Bolts with different sizes of head I6 can be employed to suit pipes I of different diameters. The pipe I is led between the bar II and the jaw I3 of each clamp and the finger nut I5 tightened to hold the pipe.

In the example taken, the first bend is a horizontal bend about a forming die A. This die has to be clamped in a horizontal plane, and in that particular case, a pair of fixing brackets I1 are employed together with a plain rectangular former arm I8. These parts are shown in greater detail in Figure 4. The bracket II consists of two plates at right angles, viz. a plate I9 for fixing the bracket in position, and a plate 20 which is drilled to enable the former arm to be fixed in any of a number of angular positions. For this purpose, the plate 20 has three drilled holes 2I, 22, 23, which lie at the corners of an equi-lateral triangle. These holes alone allow the arm I8 to be set with its centre line lying in the direction 24 which, if 'the plate 20 is vertical, is a horizontal direction, so they allow the arm I8 to be set in either of the directions 25, 26, which are at 60 to the direction 24. This is because the three holes are equi-distant and can receive two bolts 21, 28 which pass through the former arm I8. These bolts are more clearly shown in Figures '7 to 9 in which modified forms of the fixing arrangement are illustrated. The bolt 21 is a plain bolt with a shallow head secured by an ordinary hexagonal nut. The bolt r t e 2. 9 i h P ate- ?9, a d s xe by 2*,366';0it2- tightening up the nut. The bolt 28 alsozhasi a;

shallow head: butis. provided with. a. finger .nut 29 which is a spin fit. on the screw thread of the bolt 28. and. the friction of the head. of the bolt.

282 in the countersink; in the hole. in the. arm, l8, I801, Mb, or |=8c is suiiicient to prevent the bolt.

It will be noticed that. the plate 281 is drilled.

with additional holes 30 which lie along arcs between the holes Zl. and 22 on the one hand, andtheholes 2| and 23; on the. otherhand, the arcsbeing struck about the holes 23 and 22 respectiyely as centres. There are three such holes in. each set spaced apartalongeach arc, and by selecting one of the holes 22, 23 and. any one of the holes in the opposite are at 30 the arm t8 can. be set at any angular position from the direction24 to the direction 25 or 26 at. any spacing of 15 between them, as: indicatedby the chain lines in. Figure. 4 Actually, the arm til is shown as. fixed in the hole 22, and the. middle hole 38 of. the opposite series, so that in the position shown its centre line makes an angle of 30 with the. direction 24. There is an additional hole 38a allowing the arm Hi to be set vertically and, in fact, as an alternative, a series of holes like; the. holes 30 may be provided along an are extending between. the holes 22, 23 and struck about the centre of the hole 2|.. I

In. Figures 1,. 5 and 6, the forming die 3| isshown. secured to the outer end of the arm ill, by means of. a bolt 32 which has a collar 33-near one. end, and atv this end formed with an extension. 34 to serve as the pivot of the bending tool, as will be explained below. The other end of the, bolt 32 is screw-threaded to receive a. scournut. 35.. The forming die 3| is fixed to the bolt. 32-. and prevented from angular turning on it. by a pin. 35 engaging a hole in the face. of the die- 3|, and also one of anumber of notches or flutes 31 spaced around the circumference of the collar 33. The forming die 3| is formed, for

convenience, from a circular flat blank with a 'grooveof U-section formed in its periphery. Two

opposite, parallel fiat portions 3|.a (Figure 4) are milled from the original periphery which reures 5*. and; 6.. A hole is. drilled through the arm. I18. at: 3801 through bracket 4-2 (Figure 9) at right-angles to the hole which receives the bolt 32 and. breaking into that hole. The hole.

.38 receives a bolt 39 and a pair of harden-ed bushes 43m and 4812. When these bushes are loose, the bolt 312'is turned into the desired position in the former arm l8, and then the nut 4| on the. bolt 39 is tightened up, forcing the sharp edges at the inner ends. of the bushes 48a, 40b to: bite slightly into the bolt. 32. Then the upper bush 40a prevents counter-clockwise rotation of therbolt 32' and the lower bush 4153b prevents clockwise rotation of it.

' Figure 7 shows a cranked former arm |8a used instead of the straight arm |8 shown in Figure 4.. This enables the forming die 3| to be secured at an angle as illustrated in Figure 7. In Figtour of the bending part of the die is turnedat 3|c.-, the amount of metal removed being such that. the grooveshown at 3Id becomes semi-circular over the arc 3| 0 to fit the outside surface of the. pipe. to be bent. It is necessary to be able to. setthe angular position of the die 3| to set the bending con-tour 3|c of the die correctly. The. pipe is bent to the contour of the arc 3|c and one of. the. flat portions 3|a serves to limit the. bend, although as already mentioned, when the. pipe is bent against a fiat 3|a, a certain amount has to be allowed for elastic recovery of the. pipe. The. flats 310. must, however, be set at the correct. angle to determine the. desired amount of bend, and that is effected by causing the pin 36 to engage the appropriate notch or flute 31. in the collar 33.. However, it may also be arranged. for the bolt 32 to be set in any desired. angular. position in the former arm l8 and. to be. locked in the position in which. it is set. 'I'hiS v may bearranged as. shown in Fig,-

ure 8,. a cranked former arm I8bis provided, but the forming die 3| isnot fixed directly to the arm |8b, but to an angle member 42 secured to the 'former arm Nib by studs 43, the forming die 3| being fixed in the desired angular position to the angle member 42 in the same way as in Figure. 4, it is secured to the. former arm l8.

In Figure 9, the former arm IE0 is cranked twice as shown so as to bring its outer end 44 parallel tothe bracket plate 28.. In this case also an angle'member 42 secured by a stud 43 serves to carry the forming die 3|.

The die A for effecting the first bend which is in a horizontal plane has to be set horizontally, and as shown, the centre line of the former arm |8 is set at 15 to the'length of the bed 3 by employing a corner hole 22 and a hole in the opposite series next to the corner hole 23. In this case, two fixing brackets ll are, employed bolted back to back, the fixing plate I9 of the one bracket being in contact with the fixing plate IQ of the other bracket, and the drilled plate 28 of the first bracket being used for bolting it to the branch 4. of the bed. The drilled plate 2|] of the second bracket is used for fixing the former arm 8 as described.

The actual bending is effected by a lever bending=tool and a simple form of-the tool which may be used is shown in Figures'l3 and 14. The. tool consists of a stem 45to which a head 48 is welded. The head 46 is formed with alternative holes 41 for engaging the pivot 34 of the forming die. A housing 48 can slide on the stem 45 and carries a pair of rollers 49 which are opposite the, holes 41 in the sense that a line passing through the centre. of. aroller 49 andthe corresponding hole 41 is parallel to. the axis of the stem 45. A straight slipper 58 with a semi-circular groove 59a in. its upper surface to fit the pipe I, is mounted in the housing 48, resting upon the rollers 49 and guided by pins 5| in the housing 48 engaging grooves in the opposite sides of the slipper 58. The lower end of the stem 45 is screw-threaded and receives a nut 52. By screwing down this nut, the housing 48 can slide away from the head 46 so that the latter can engage the pivot 34 with the pipe I to be bent threaded between the slipper 50 and the bending die 3|, whereupon by tightening the nut 52, the housing 48 can be pushed up until the slipper 50 is in contact with the pipe and the rollers 49 bear on the rear face of the slipper 58. As shown in -Figures l3 and 14, the parts are in position for starting a counter-clockwise bend, the left-hand roller 49 efiecting the nip between the pipe and the'forming die 3| and as the bending tool is turned counter-clockwise. about. the pivot 34', the

right-hand roller 49 which is in advance, pushes up the. slipper 50 to commence the bending of the pipe which is completed .against the fiat 3la of the die 3|. In the case of a clockwise bend, the right-hand hole 41 is engaged with the pivot 34 and the right-hand roller 49 then takes the nip against the pipe and the tool is turned clockwise.

Referring again to Figures 1 to 3, the second bend is a horizontal bend to be made about the forming die B close to it in the opposite direction to the first bend. It will be noted that the die B is mounted on a former arm l8 fixed to a pair of brackets I! in a manner very similar to the die A except that the former arm in this case is set at an angle of 30 to the length of the bed 3 by selecting a hole 30 in the plate 20, which is in the middle of the series. It will also be noted that the former B has set up interference with the placing of the pipe 1 between the clamps 9 and the setting stop 2, so that in the first setting, the die B and indeed also the die C which will be referred to later,have to be moved out of the way, and this is done by swinging the former arms 18 in the manner already described about the bolts 21. It will be noticed that for convenience the brackets for the die B are fixed to the base 3 on the opposite side of the general run of the pipe I from those used for the first bend.

The third bend is made at the die C which is fixed in position in a manner similar to the die B, but it will be noticed that owing to the amount desired for the bend at the'die C, this die is set in a different angular position with respect to its former arm Hi from the position of the die B with respect to its former arm.

The fourth bend is effected at the die D and the bend is such that the pipe IA has to pass below the die D and to be bent upwardly from the base 3. Therefore, the die D is set at the desired angle by the use of a bracket IT as already described, a plain straight former arm 18, and an angle member 42 secured as already described with reference to Figures 8 and 9. Then, in order to finish this end of the pipe, a bend has to be made over the die E so that the end of the tube finally projects vertically downwards as indicated at 53. In this case, therefore, the die E is fixed directly to a former arm l8 secured to a bracket H at the desired angle to give the proper position for the die E.

The sixth bend is made on the other end of the pipe I to the right of the clamps 9, as shown best in Figure 3. In fact, a right-angle bend in a horizontal plane is made around the die F. The fixing of this die on its former arm I8 is very similar to a fixing of the die B except, of course, that the arm I8 projects in the opposite direction from the bracket [1, and as a rightangle bend has to be made, the die F is set in a different angular position on the arm IS.

The seventh bend is made about the die G which is fixed to a double cranked former arm I80 similar to that shown in Figure 9 except that the die G is secured direct to the arm [80 without interposing one of the angle members 42. The arm 180 is fixed at the desired angle to one of the standardised brackets H. The pipe is bent down and under the die G, and then the eighth or final bend is made around a die H, bringing the end of the pipe IA so as to extend vertically upwards. The die H is parallel to and in the same plane as the die G to produce a right-angle bend, and it is mounted on a simple rectangular former arm l8 secured to the standardised fixing brackets I! in the manner already described.

Generally speaking, the pipe has to be held down to each forming die at the commencement of a bend to prevent it springing away, and any suitable cramp may be used for that purpose, sucl'r as that described in patent application Serial No. 473,737 already referred to.

We claim:

l. A fixing jig for dies for bending metal tubes or rods comprising an angle bracket consisting of a pair of integral flat plates at right-angles to each other, one of said plates being perforated with three holes each lying at a corner of an equilateral triangle and with series of holes lying on circular arcs each of which extends from one corner of said triangle to another corner thereof and which is struck about the third corner of said triangle as center, a die-carrying arm, a pair of bolts passing through spaced holes in said arm and through one corner hole in said plate and through one of the holes of the opposite series to fix said arm to said plate and a profiled bending die secured to the free end of said arm and formed as a flat plate with a rim grooved to receive the bent tube or rod.

2. A fixing jig for dies for bending metal tubes or rods comprising an angle bracket consisting of a pair of integral fiat plates at right-angles to each other, one of said plates being perforated with a series of holes lying on a circular arc struck about another hole in the plate as center, an arm contacting said plate, a pair of bolts passing through spaced holes in said arm and through said other hole in said plate and through one of the holes of the arcuate series to fix said rm to said plate, a right-angle die-carrying member bolted to the free end of said arm and a profiled bending die plate secured to said die-carrying member and formed as a fiat plate with a rim grooved to receive the bent metal tube or rod.

3. A fixing jig for dies for bending metal tubesor rods comprising an angle bracket consisting of a pair of integral fiat plates at right-angles to each other, one of said plates being perforated with a series of holes lying on a circular arc struck about another hole in the plate as center, a diecarrying arm, a pair of bolts passing through spaced holes in said arm and through said other hole in said plate and through one of the holes of the arcuate series to fix said arm to said plate, a profiled bending die plate, and a bolt securing said die plate to the free end of said arm and extending to form a pivot for a lever-like bending tool.

4. A fixing jig for dies for bending metal tubes or rods comprising an angle bracket, consisting of a pair of integral fiat plates at right-angles to each other, one of said plates being perforated with a series of holes lying on a circular arc struck about another hole in the plate as center, an arm contacting said plate, a pair of bolts passing through spaced holes in said arm and through said other holes in said plate and through one of the holes of the arcuate series to fix said arm to said plate, a right-angle die-carrying member bolted to the free end of said arm, a profiled bending die plate, and a bolt securing said die plate to the free end of said arm and extending to form a pivot for a lever-like bending tool.

5. A fixing jig for dies for bendingmetal tubes or rods comprising a die-carrying member, a profiled bending die plate, a bolt passing through said die plate and said die-carrying member to secure same together, a further bolt passing through said member at right-angles to the axis of said first-named bolt, a pair of hardened bushes surrounding said further bolt and means for tightening said bushes to cause same to lock said first-named bolt in adjusted angular position.

6. A jig for spacing and mounting dies for bending metal tubes or rods comprising a mounting bed, a plurality of fixing brackets secured in spaced relationship to saidbed and each comprising a pair of flat plates at right-angles to each other, one of said plates being perforated with a series of holes lying on a circular arc struck about another hole in the plate as center, and a plurality of die-carrying arms each fastened to one of said fixing brackets.

7. A jig for spacing and mounting dies for bending metal tubes or rods comprising a mounting bed, a plurality of fixing brackets secured in spaced relationship to said bed and each comprising a pair of flat; plates at right-angles to each other, one of said plates being perforated with a series of holes lying on a circular arc struck about another hole in the plate as center, a plurality of die-carrying arms each fastened to one of said fixing brackets, and a setting stop also secured to said bed and comprising an upstanding bar and an adjustable set-screw threaded in said bar to be engaged before the commencement of bending by the end of the metal tube or bar to be bent.

8. A jig for spacing and mounting dies for bending metal tubes or rods comprising a mounting bed, a plurality of fixing brackets secured in spaced relationship to said bed and each comprising a pair of flat plates at right-angles to each other, one of said plates being perforated with a series of holes lying on a circular arc struck about another hole in the plate as center, a plurality of die-carrying arms each fastened to one of said fixing brackets, and at least one clamp for supporting the tube or rod to be bent at an intermediate point also secured to said bed and comprising an upstanding bar with spaced perforations, a jaw for gripping the tube or rod to be bent, and a bolt passing through said jaw and the appropriate perforation in said bar for fixing said jaw to said bar.

FREDERICK CECIL DRAPER. JOHN SHAW. 

